refugium

A locality that has escaped drastic alteration following climatic change,
in constrat to the region as a whole. A refugium usually forms a center
for relic species. Refugia exist widely over the Earth's surface because
although, owing to glacial advance and recession, changes of climate affecting
the survival of plants and animals have occurred, no general climatic change
affects a large area uniformly, with the result that relic colonies of species
or communities, are left behind.